Screen with vibration-isolated vibration generator



June 13, 1967 G. ERLENSTADT ETAL 3,325,007

SCREEN WITH VIBRATION-ISOLATED VIBRATION GENERATOR 3 Sheets-Sheet 1 Filed Dec. 14, 1964 lNVENTORf-i Gii nter Erlenstfidt &

Harald Dfirner BY WZGWV June 13, 1967 G. ERLENSTADT ETAL 3,325,007

SCREEN WITH vwmnowxsommu VIBRATION GENERATOR 3 Sheets-Sheet 2 Filed Dec. 14, 1964 5 R m V m Gijnter ,Erlenstddt 8: Harold Dbrner wai /0; W

ATTORNEYS June 13, 1967 G. ERLENSTADT ETAL 3,325,007

SCREEN WITH VIBRATIONISOLATED VIBRATION GENERATOR Filed Dec. 14, l964 5 Sheets-Sheet Z INVENTORS Giinter Erlenstiidt a Harold Dtirner BY/%Mcwj@@ ATTORNEYS United States Patent Claims. cl. 209-315 The present invention relates to a screening machine; more particularly, to a screening machine wherein the screen mesh is directly driven by means of vibratory drives which are attached directly to the mesh.

In a known type of screening machine, a stationaryrnounted screen frame, or riddle, is driven by means of vibratory drives, which are distributed above the screen surface. Each of these drives is fashioned as an electromagnet, and they excite the screen mesh directly. This type of screening machine has the disadvantage that the many electromagnets which are required necessitate a large expenditure, making the machine undesirable from the standpoint of economics.

It is therefore an object of the present invention to provide a screening machine in which the desirable features of known devices are retained, while avoiding their disadvantages.

It is a further object of the present invention to provide a screening machine which is simple, and which operates with a high degree of efficiency.

Another object of the present invention is to provide a screening machine wherein vibratory drives made up of resilient, tuned vibrating elements are distributed across the screen mesh surface to drive the screen, and are in turn driven by a vibration generator mounted on an auxiliary mass, which mass is vibration-isolated from the screening machine.

These objects, along with others, are accomplished by providing, a screening machine, including a screen frame and screen, wherein vibratory drives which are resilient, tuned vibrating elements, are distributed across the surfaces of the screen mesh, and are driven via one or more vibration generators. Each vibration generator is mounted on an auxiliary mass, which is itself mounted so that it is vibration-isolated from the screening machine.

Additional objects and advantages of the present invention will become apparent upon consideration of the following description when taken in conjunction with the accompanying drawings in which:

FIGURE 1 shows an embodiment of a screening machine constructed according to the present invention, in longitudinal section.

FIGURE 2 shows a further embodiment of the present invention, in longitudinal section, in which more than one vibration generator is utilized.

FIGURE 3 shows still another embodiment of the present invention, in longitudinal section, in which a plurality of screens are arranged in different tiers, one above the other.

In an advantageous embodiment of the present invention, the screening machine is held stationary, in a manner well known, and the auxiliary mass carrying the vibration generator is mounted in such a way that it is vibration-isolated from the screening machine and riddle.

In another embodiment of the invention, the vibrating elements are divided into groups, and each group is driven by a separate vibration generator which is mounted on an auxiliary mass such that it is vibration-isolated from the screening machine. In addition, each vibration generator is preferably separately controllable.

In still another embodiment of the present invention, several screens provided at one screening machine, and each having resiliently tuned vibrating elements, may be used. These screens are driven by a common vibration generator mounted on an auxiliary mass, and the mass is mounted so that it is vibration-isolated from the screening machine. An embodiment such as that last-mentioned may be constructed in which the vibrating elements driving each screen are driven by a vibration generator which drives only that particular screen. Each of these vibration generators is mounted on an auxiliary mass in a vibrationisolated manner, and each generator is preferably separately controllable.

In the previously mentioned embodiment, the screens may be arranged in a so-called double-tier or multipletier arrangement, one above the other, and provided with a common vibration generator. Separate vibration generators may be provided in place of the single common vibration generator.

In all of the foregoing embodiments, constructed according to the present invention, a heretofore unachieved quietness of operation is obtained. These screening machines are highly economical, even with high screen loads, and are practically maintenance-free. They can be adjusted to screen any type of substance. In all of the above embodiments, the electromagnetic drives may be those -well known to persons of ordinary skill in the art.

Referring more specifically to the figures of the drawings, the screen machine shown in FIGURE 1 includes a stationary screening box 1 having a screen frame, or riddle 2 with a screen 3 mounted on it. The screen frame is inclined with respect to the horizontal. Above the screen 3, there is a cover 4 with an inlet 5 for the goods to be screened, and an outlet 6 for the goods remaining on top of the screen after a screening operation. Screen 3 is excited by tappets 7 which are mounted vertically with respect to the screen.

These tappets are resiliently mounted at the auxiliary mass 9 by means of resilient elements 7, which may be of rubber, for example, and are tuned to vibrate the screen at a fundamental frequency. These tappets are driven by a common electromagnetic drive 10. This electromagnetic drive 10 is mounted on an auxiliary mass 9, which in turn is mounted on cover 4 of the screening box 1 so as to be vibration-isolated therefrom. Vibration isolation is provided by mounting the auxiliary mass 9 to the screening box cover 4 by means of spring elements 8, which are, for instance, rubber or metal springs. Packing 13 is placed between various ones of the elements of the machine. Flanges 12 may be used to couple the tappets 7 to the screen.

In the embodiment of the invention illustrated in FIG- URE 2, the reference numerals for those elements which are substantially the same as in the embodiment of FIG- URE 1 are the same as those used in FIGURE 1. The tappets 7 form two groups 13' and 14 of two tappets each. Each of these groups is driven by a separate electromagnetic drive (10, 10'), each of which is mounted on a separate auxiliary mass (9, 9'). These auxiliary masses are vibration-isolated from the screening box cover 4.

In the embodiment of the invention illustrated in FIGURE 3, there is shown a screening machine incorporating an additional screen 3', the two screens 3 and 3' being arranged in tiers with each screen forming a tier and the two screens being arranged one above the other. Each tappet 7 is provided with an extension 11 that reaches to the second screen 3' As is shown in FIGURE 3, the screen 3' is arranged within an intermediate frame 14 which is below the screen. The intermediate fraction, i.e., the material passed through the screen 3 but not through the screen 3', is eliminated from the screening machine through the funnel-like outlet 13.

It will be appreciated that more than two screens may be stacked above each other.

It will be understood that the above description of the present invention is susceptible to various modifications, changes, and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.

What is claimed is:

1. A screening machine comprising, in combination:

(a) means defining a stationary screening box and at least one screen mounted on said box;

(b) a plurality of vibratory drive means extending in a direction having at least a component normal to said screen, said drive means being tuned to a fundamental frequency and connected to said screen at spaced points therealong;

(c) electromagnetic vibration generating means;

((1) at least one auxiliary mass supporting said vibration generating means and connected to said vibratory drive means for transmitting vibrations produced by said vibration generating means to said drive means and said screen to vibrate said screen at such fundamental frequency; and

(e) vibration-isolating mounting means mounting said auxiliary mass on said screening box for insulating said screening box from the vibrations of said auxiliary mass and said vibration generating means.

2. An arrangement as defined in claim 1 wherein said vibratory drive means are divided into at least two groups, said electromagnetic vibration generating means are composed of at least two electromagnetic vibration generating units, and there are provided at least two auxiliary masses, and wherein each said auxiliary mass supports a respective one of said vibration generating units and is connected to a respective one of said groups of vibratory drive means.

3. An arrangement as defined in claim 2 wherein each of said vibration generating units is independently controllable.

4. An arrangement as defined in claim 1 wherein there are provided a plurality of screens mounted on said screening box.

5. A screening machine as defined in claim 4, wherein said plurality of screens are arranged in tiers, each said screen of said plurality forming a tier.

References Cited UNITED STATES PATENTS 2,880,871 3/ 1959 Bruninghaus 2093 10 3,024,912 3/1962 Jakobs 209-310 X 3,179,251 3/1965 Nickel 209-347 X HARY B. THORNTON, Primary Examiner.

R. HALPER, Assistant Examiner. 

1. A SCREENING MACHINE COMPRISING, IN COMBINATION: (A) MEANS DEFINING A STATIONARY SCREENING BOX AND AT LEAST ONE SCREEN MOUNTED ON SAID BOX; (B) A PLURALITY OF VIBRATORY DRIVE MEANS EXTENDING IN A DIRECTION HAVING AT LEAST A COMPONENT NORMAL TO SAID SCREEN, SAID DRIVE MEANS BEING TUNED TO A FUNDAMENTAL FREQUENCY AND CONNECTED TO SAID SCREEN AT SPACED POINTS THEREALONG; (C) ELECTROMAGNETIC VIBRATION GENERATING MEANS; (D) AT LEAST ONE AUXILIARY MASS SUPPORTING SAID VIBRATION GENERATING MEANS AND CONNECTED TO SAID VIBRATORY DRIVE MEANS FOR TRANSMITTING VIBRATIONS PRODUCED BY SAID VIBRATION GENERATING MEANS TO SAID DRIVE MEANS AND SAID SCREEN TO VIBRATE SAID SCREEN AT SUCH FUNDAMENTAL FREQUENCY; AND (E) VIBRATION-ISOLATING MOUNTING MEANS MOUNTING SAID AUXILIARY MASS ON SAID SCREENING BOX FOR INSULATING SAID SCREENING BOX FROM THE VIBRATIONS OF SAID AUXILIARY MASS AND SAID VIBRATION GENERATING MEANS. 